/*
 * Copyright 2007 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*namespace com.google.zxing.qrcode.decoder {*/

import Version from './Version'
import ECBlocks from './ECBlocks'
import ECB from './ECB'
import ErrorCorrectionLevel from './ErrorCorrectionLevel'
import Exception from './../../Exception'

/**
 * <p>Encapsulates a block of data within a QR Code. QR Codes may split their data into
 * multiple blocks, each of which is a unit of data and error-correction codewords. Each
 * is represented by an instance of this class.</p>
 *
 * @author Sean Owen
 */
export default class DataBlock {

  private constructor(private numDataCodewords: number /*int*/, private codewords: Uint8Array) {}

  /**
   * <p>When QR Codes use multiple data blocks, they are actually interleaved.
   * That is, the first byte of data block 1 to n is written, then the second bytes, and so on. This
   * method will separate the data into original blocks.</p>
   *
   * @param rawCodewords bytes as read directly from the QR Code
   * @param version version of the QR Code
   * @param ecLevel error-correction level of the QR Code
   * @return DataBlocks containing original bytes, "de-interleaved" from representation in the
   *         QR Code
   */
  public static getDataBlocks(rawCodewords: Uint8Array,
                                  version: Version,
                                  ecLevel: ErrorCorrectionLevel): DataBlock[] {

    if (rawCodewords.length != version.getTotalCodewords()) {
      throw new Exception(Exception.IllegalArgumentException)
    }

    // Figure out the number and size of data blocks used by this version and
    // error correction level
    const ecBlocks: ECBlocks = version.getECBlocksForLevel(ecLevel)

    // First count the total number of data blocks
    let totalBlocks = 0
    const ecBlockArray: ECB[] = ecBlocks.getECBlocks()
    for (const ecBlock of ecBlockArray) {
      totalBlocks += ecBlock.getCount()
    }

    // Now establish DataBlocks of the appropriate size and number of data codewords
    const result = new Array<DataBlock>(totalBlocks)
    let numResultBlocks = 0
    for (const ecBlock of ecBlockArray) {
      for (let i = 0; i < ecBlock.getCount(); i++) {
        const numDataCodewords = ecBlock.getDataCodewords()
        const numBlockCodewords = ecBlocks.getECCodewordsPerBlock() + numDataCodewords
        result[numResultBlocks++] = new DataBlock(numDataCodewords, new Uint8Array(numBlockCodewords))
      }
    }

    // All blocks have the same amount of data, except that the last n
    // (where n may be 0) have 1 more byte. Figure out where these start.
    const shorterBlocksTotalCodewords = result[0].codewords.length
    let longerBlocksStartAt = result.length - 1
    // TYPESCRIPTPORT: check length is correct here
    while (longerBlocksStartAt >= 0) {
      const numCodewords = result[longerBlocksStartAt].codewords.length
      if (numCodewords === shorterBlocksTotalCodewords) {
        break
      }
      longerBlocksStartAt--
    }
    longerBlocksStartAt++

    const shorterBlocksNumDataCodewords = shorterBlocksTotalCodewords - ecBlocks.getECCodewordsPerBlock()
    // The last elements of result may be 1 element longer
    // first fill out as many elements as all of them have
    let rawCodewordsOffset = 0
    for (let i = 0; i < shorterBlocksNumDataCodewords; i++) {
      for (let j = 0; j < numResultBlocks; j++) {
        result[j].codewords[i] = rawCodewords[rawCodewordsOffset++]
      }
    }
    // Fill out the last data block in the longer ones
    for (let j = longerBlocksStartAt; j < numResultBlocks; j++) {
      result[j].codewords[shorterBlocksNumDataCodewords] = rawCodewords[rawCodewordsOffset++]
    }
    // Now add in error correction blocks
    const max = result[0].codewords.length
    for (let i = shorterBlocksNumDataCodewords; i < max; i++) {
      for (let j = 0; j < numResultBlocks; j++) {
        const iOffset = j < longerBlocksStartAt ? i : i + 1
        result[j].codewords[iOffset] = rawCodewords[rawCodewordsOffset++]
      }
    }
    return result
  }

  public getNumDataCodewords(): number /*int*/ {
    return this.numDataCodewords
  }

  public getCodewords(): Uint8Array {
    return this.codewords
  }

}
